IBRC #32-B-10

Idaho Bird Records Committee
Rarities Report Form

Species: Whimbrel

Reporter:
Cliff Weisse
4125 Beaver Springs Rd.
Island Park, ID 83429
cliffandlisa@octobersetters.com

Other Observers: Lisa Weisse, Darren Clark (clarkd@byui.edu)

Date of Observation: 9-17 May 2010
Date Report Prepared: 4 June 2010

Locality of Observation: Island Park Reservoir, at the mouth of the old Sheridan Creek channel at the extreme west end of the reservoir.

Habitat: various shoreline habitats (no mud flats present)

Conditions:  Various.  The bird was observed on 5 different days at distances ranging from 1/4 mile to 20 yards in all light conditions.  

Did you take notes… No

Did you consult a field guide or other reference work?  Yes, later the same day.  Guides consulted were Big Sibley and Paulson's Shorebirds of the Pacific Northwest

Description: Large sandiper about the size of Marbled Godwits with medium length legs and long bill.  Overall brown above with paler whitish underparts.  Upperparts feather were medium/dark brown with whitish edges and notches.  Underparts whitish, flanks buff with even dark brown vertical barring.  Breast and throat heavily streaked with brown.  Tail barred with brown and tan with dark lines much wider than pale lines.  Head striped with brown and tan-median crown stripe tan, crown dark brown, supercilium tan, dark transocular stripe, brownish auriculars and tannish cheeks.  Bill long (approximately 2x head length), decurved (more so at tip than at base), and with reddish base of lower mandible.  Bill obviously shorter the Long-billed Curlew and Marbled Godwit in direct comparison.  Legs gray.  Belly around base of legs did not show long thin feathers.  

Behavior: Foraging with Marbled Godwits most of the time.  When first observed on the 9th I heard it call and located it alone on a small island.  It soon flew over and joined a flock of 8-9 Marbled Godwits and walked off into sagebrush.  On other dates it was in moist grassy shoreline areas foraging with Marbled Godwits.  It allowed fairly close approach, probably because the godwits had been present for a while and become used to my presence, allowing me to approach closer than when first observed.  

How and when did you positively identify the bird, and what clinched the identification for you?  Immediately upon hearing the call, an evenly spaced series of loud clear whistles, very unlike the sputtering slurred notes of Long-billed Curlew.  Further scrutiny revealed the field marks noted above and the lack of long thin feathers around the legs eliminated Bristle-thighed Curlew, which I later realized exhibits obviously different plumage characteristics in breeding plumage.

How did you eliminate similar species, and what were they?  
The only similar shorebirds are other curlews and possible Marbled Godwit.  
-Marbled Godwit is easily eliminated by lack of cinnamon tones and the decurved bill.
-Long-billed Curlew has much longer bill, cinnamon tones on the body and especially on the wings, and a very different call.
-Bristle-thighed Curlew is more similar but has cinnamon barring on tail, more heavily streaked and higher contrast streaking on the breast and throat, blacker feather centers on upperparts creating more contrasty appearance, some centers of scapulars bright golden buff.  The "bristles" were specifically looked for at close range with 60x spotting scope and not seen but I feel plumage characteristics are a better choice for separating Whimbrel from Bristle-thighed Curlew in breeding plumage.  In basic plumage, Bristle-thighed differs even more by having brown centered scaps with bright golden buff edges and notches and darker cinnamon buff breast and underparts.

Experience with this species: I've seen 4 Whimbrels in Idaho and a handful in NJ, hundreds of LB Curlews annualy, never seen a Bristle-thighed Curlew.

General experience birding: about 16 years

Were photo(s), video, and/or audio obtained by you?  Yes